Diatoms are organisms that produce a significant amount of the world's what?

Never heard of them, I’ll try not to stand on them in future…

Player #25874027, while it would very likely vary by area, the 20%-50% statistic refers to the amount of oxygen produced for the entire planet. This broad statistic would likely imply that nobody is certain but the answer falls within this range.

Arohanui, it probably varies by area

amazing little organisms